The purpose of this application is to support my advanced training in patient-oriented research with the goal of becoming an independently funded investigator studying disorders of hemostasis in children. I will achieve this objective with the help of a rich and supportive environment at my institution, The University of Texas Southwestern Medical Center at Dallas (UT Southwestern). This milieu includes an experienced mentor, Dr. George R. Buchanan, and a robust training infrastructure, The Center for Biostatistics and Clinical Science, which will oversee my formal academic training. Coursework, seminars and individual instruction will complement hypothesis-driven research projects as requirements for a Master's Degree in Clinical Science that I plan to obtain. The Department of Pediatrics at UT Southwestern has committed its full support to my endeavors to be trained in clinical research through the institution's Clinical Scholars Program. Moreover, Children's Medical Center- Dallas has one of the largest pediatric cancer programs in the country allowing not only for recruitment of study participants but for assistance of outstanding research coordinators and enthusiastic support of hematology-oncology colleagues. The mentored research project that I will conduct concomitantly with the formal training in clinical investigation involves central venous catheter (CVC)-related thrombosis. Children with cancer frequently have catheters placed to facilitate their therapies, but CVCs are associated with serious complications (e.g. thrombosis). The risk factors, management and outcome of catheter-related deep vein thrombosis (DVT) are unknown. Having already gained initial research experience in this study area, I have chosen to conduct a two phase study with the aims of 1) defining by means of a prospective cohort design whether catheter occlusion or bacteremia heralds the presence of occult DVT in children with cancer; and 2) determining through a randomized clinical trial whether treating occult (or asymptomatic) DVT with anticoagulation will prevent subsequent adverse catheter events defined as development of symptomatic thrombosis, bacteremia, or need for catheter replacement. Design and implementation of this study in conjunction with the structured activities listed above will provide the means for me to develop skills in patient-oriented research, teaching and presenting data, and mentoring, thus launching a long and successful career as an independent clinical investigator.